A variety of electrical connectors have been used to make electrical connections between the circuits on different printed circuit boards. In board-to-board connectors, male and female terminals form an electrical connection between the two circuit boards. Male connector posts or pins typically are coupled to a first circuit board, and the male connector posts mate with female connector terminals coupled to the second circuit board. In some connectors, the terminals may be hermaphroditic and include both male and female portions.
Terminals for such connectors typically are stamped out of thin sheet metal material, and the terminals are fixed in an elongated insulating housing at regular intervals longitudinally thereof. Each terminal includes a contact beam, arm or post for contacting a complementary terminal in the associated mating connector housing. Typically, the contact arm is cantilevered from a base which is integral with the contact arm and which is fixed to the connector housing. A retention arm also might extend from the base for rigidly retaining the terminal in the housing. The contact arm of the terminal preferably is sufficiently flexibly rigid to facilitate a positive engagement and disengagement with the complementary terminal of the mating connector, but the flexible contact arms of all of the terminals in the connector must not be too rigid so as to require an excessive force when mating and unmating the connectors. The flexibility of the contact arm can be increased by increasing the length of the arm or reducing the width of the arm measured in the plane of the sheet metal material.
Problems have been encountered with these types of electrical connector systems because there is an ever-increasing demand for higher density connectors and for allowing printed circuit boards to be placed closer together. High density connectors often reduce the spacing between the terminals of a given connector, but the thickness of the terminals cannot be manipulated beyond given parameters. To allow printed circuit boards to be placed closer together in parallel planes, a very low profile connector is required which, in turn, limits the length of the contact arms of the terminals.
A corollary problem arises when the spacing between the terminals is reduced to increase the density of the connectors. Since the thickness of the sheet metal material of the terminals cannot be reduced beyond practical limits, there is an increasing probability that the flexible contact arm of any given terminal might engage a complementary terminal of the mating connector which is on one or the other side of the given terminal instead of the correct complementary terminal with which the given terminal is intended to engage.
The present invention is directed to solving these various problems by providing improvements in the electrical terminals of electrical connectors of the character described.